MonthWithoutAFullMoon.frink

// A program to disprove the e-mail that says,// "February 1865 is the only month in recorded history not to have a full// moon."

// For a month to have no full moon, the illuminated fraction has to be// decreasing at the beginning of the month and increasing at the end of// the month. This will only work in February because a lunar month is// 29.5305555 days.

// Start with the first February after the Gregorian calendar was adopted// (which was October 15, 1582)
for year = 1583 to 2020
{
start = parseDate["$year-02-01 00:00 $timezone"]
end = parseDate["$year-03-01 00:00 $timezone"]